Answer:
Isolation allowed China to develop on its own, without too much interference from foreign invasion.
Step-by-step explanation:
Even though nomadic invaders came and sometimes took over, they ended up joining and adopting the Chinese cultures and ways.
"More often, the outsiders whom the Chinese encountered were nomadic invaders. To the Chinese, these nomads were barbarians who did not speak Chinese and lacked the skills and achievements of a settled society. Nomads conquered China from time to time, but they were usually absorbed into the advanced Chinese civilization.